1. Field of the Invention
The present invention is a novel process for the synthesis of alkyl cycloalkyl dialkoxysilanes.
2. Description of the Prior Art
V. Bazant et al., in Organosilicon Compounds, Vol. 2.sup.1 (1965) on pages 8, 350 and 482 names methyl cyclohexyl dimethoxysilane and appears to indicate its synthesis by a Grignard route by citation of an article by S. Chrzczonowicz et al. in Rocniki Chemii, Vol. 32, 155-157 (1958) which is abstracted in Chemical Abstracts, Vol. 52, 16188a (1958). A closer examination of the disclosure of this cited reference, however, indicates that the content of this publication is limited to the hydrolysis of dialkyldimethoxysilanes.
Z. Lasocki in Bull. Acad. Polon. Sci., Ser. Sci. Chim. 12(5) 281-287 (1964), abstracted at Chemical Abstracts, 61, 13339a, mentions the Grignard synthesis of methyl cyclohexyl dimethoxysilane in only 40% yield, apparently from silicon tetrachloride or from trichloromethylsilane using an ethyl ether solvent.
S. Chrzczonowicz et al. in Roczniki Chemii, Vol, 34, 1667-1774 (1960), abstracted in Chemical Abstracts, Vol. 56, 7344h indicates the formation of methyl cyclohexyl dimethoxysilane from tetramethylsilicate by a Grignard reaction in an ether solvent.
None of the aforementioned references show or clearly suggest the formation of an alkyl cycloalkyl dialkoxysilane, in the absence of an ether solvent, from an alkyl trialkoxysilane (as contrasted to use of silicon tetrachloride, trichloromethylsilane, or tetramethylsilicate) with a Grignard reagent containing the cycloalkyl group intended in the final product.
The use of alkyl trialkoxysilane starting materials in a Grignard synthesis is mentioned by V. Bazant et al. (in Organosilicon Compounds, Vol. 1, pp. 184-185) who indicate that alkoxysilane starting materials have certain advantages over the use of chlorosilanes: their greater stability towards hydrolysis and the fact that the reaction can be carried out without solvent. However, the yield of product is said to be generally lower and the steric effects are said to be more important than in the halogenosilanes. On page 185 Bazant et al. cites as "CJ-6" the preparation of methyl phenyl diethoxysilane in yields of 60-66% by reaction of methyl triethoxysilane with chlorobenzene and magnesium metal. This work was originally reported by V. Capuccio et al., Chimico e industria (Milan) 33, 282-283 (1951) and is abstracted in Chemical Abstracts, Vol. 47, 2724g. It also fails to show or suggest Grignard synthesis of alkyl cycloalkyl dialkoxysilanes from an alkyl trialkoxysilane, since it, rather, contains an isolated disclosure of synthesis of methyl phenyl diethoxysilane.